2014 marked the passing of six conductors whose response to a transforming world both embraced and challenged tradition for over six decades.

Each year brings the loss of beloved artists and musicians, men and women whose creative impulse enlivened concert halls and opera houses around the world. 2014 has been no different. But among those who passed away during the last 12 months are six conductors who, each in his own way, represented a particular response to a tumultuous world and the art of conducting.

The middle of the 20th century was a time of unprecedented technological progress, cultural upheaval, and political brinksmanship. In the the midst of it, the aesthetic values and imperatives of the past were at risk. But there was also opportunity for new perspectives to challenge stale assumptions.

Rafael Frühbeck de Burgos (Sept. 15, 1933 - June 11, 2014) fully embraced the values of past masters, with an interpretive voice that highlighted, as Jeremy Eichler of the Boston Globe put it in his obituary, the "monumentality" of classical music. Even in his later years, often conducting from a chair, his gestures and pacing carried a certain dignity and civility, as you'll see in this video:

Julius Rudel (March 6, 1921 - June 26, 2014) spent his formative years in Vienna before fleeing with his family as the Nazi's grip on power tightened. Steeped in the performances of the Vienna State Opera, he went on to become the heart and soul of the New York City Opera. His technique was one of compact efficiency, but one that elicited passion and power, qualities you'll see in this 1988 performance in Hungary:

American conductor Lorin Maazel (March 6, 1930 - July 13, 2014) was, by all accounts, one of the most brilliant arists to ever stand in front of an orchestra. His interpretations could be confounding at times, but his commitment to the art was never in doubt. This performance of the Adagietto from Mahler's Symphony No. 5 is rendered with confidence and security:

Frans Brüggen (Oct. 30, 1934 - Aug. 13, 2014) came of age in a Europe of reconstruction and an era of challenge to authority. For him, the grandiosity of classical music smacked of inauthentic posturing, and he actively protested the conservative programming of the Concertgebouw Orchestra in his native Amsterdam. That rebellious energy was channeled into the burgeoning early music movement, which led to the founding of the Orchestra of the 18th Century and visceral yet elegant performances like this:

Christopher Hogwood (Sept. 10, 1941 - Sept. 24, 2014) was also an early music pioneer. His challenge to received wisdom and interpretation took on a scholarly, direct approach. When accused of producing music devoid of emotion, his response was that the musical discourse of earlier centuries had a wholly different relationship to emotion. His conducting was full of energy and impulse, as you'll see here:

Claudio Abbado (June 26, 1933 - Jan. 20, 2014) has been remembered by those who worked with him as having brought an uncommonly honest, emotionally direct, and humane approach to making music. As the successor to Herbert von Karajan at the Berlin Philharmonic, Abbado maintained the superb level of that ensemble while infusing concerts with a reverence for the composer, whatever the music. He was also an orchestra builder, founding groups like the European Community Youth Orchestra (out of which grew the Chamber Orchestra of Europe) and the Gustav Mahler Youth Orchestra (which led to the formation of the Mahler Chamber Orchestra). In 2003 he founded the Lucerne Festival Orchestra, which he conducts in this performance of Mahler's Symphony No. 9: